Added value of enhanced CT on LR-3 and LR-4 observation of Gd-EOB-DTPA MRI for the diagnosis of HCC: are CT and MR washout features interchangeable?

Objective: To characterize the use of portal venous or delayed phase CT as an alternative to estimate washout for the non-invasive diagnosis of hepatocellular carcinoma (HCC) on gadoxetic acid-enhanced MRI in combination with other features. Methods: This retrospective study included 226 observations (n = 162 patients) at high risk for HCC imaged with gadoxetic acid-enhanced MRI and enhanced liver CT between March 2015 and March 2018. Two radiologists independently evaluated two sets of images and assigned the final Liver Imaging Reporting and Data System (LI-RADS) categories by consensus using gadoxetic acid-enhanced MRI. LR-1, LR-2, LR-5, and LR-M were excluded from the study. The observations were divided using different criteria for washout: hypointensity on the portal venous phase (PVP) at MRI (criteria 1), hypointensity on PVP at MRI and/or hypoattenuation on the PVP/delayed phase at dynamic CT (criteria 2), and hypointensity on the PVP and/or hepatobiliary phase at MRI (criteria 3). The sensitivity, specificity, and accuracy for the diagnosis of HCC were analyzed for each criterion. Results: Using gadoxetic acid-enhanced, 226 lesions were diagnosed as LR-3 or LR-4 by LI-RADS. Among them, 98 and 152 had “washout” at criteria 1 and 2, respectively. For the diagnosis of HCC, criteria 2 and 3 showed significantly higher sensitivities (67.3 and 92.5%, respectively) compared with criteria 1 (35.5%) (p < 0.001). The specificity of criteria 3 (13%) was significantly lower than those of criteria 1 and 2 (40.7% and 38.4%, respectively, p < 0.001). The specificities between criteria 1 and 2 were not statistically different (p = 0.427). Conclusion: Although the LI-RADS lexicon does not permit the interchange of image features among various image modalities, the sensitivity of HCC diagnosis could be improved without any decrease in specificity by adding CT image washout features. Advances in knowledge: Although the LI-RADS lexicon does not permit the interchange of image features among various image modalities, complementary use of dynamic CT in LR-3 or LR-4 categories on the basis of gadoxetic acid-enhanced MRI may contribute to major imaging feature.

P-L01 Newly detected liver nodules with a history of colorectal cancer: are they metastasis?

Background The diagnosis of newly detected liver nodules in patients with colorectal cancer (CRC) is crucial for determining prognosis and treatment. Accurate identification of benign nodules can help avoid unnecessary therapy. The aim of our study was to retrospectively review CRC patients who underwent liver resection for newly detected liver nodules in our institution. Methods We went over all patients with a history of CRC, who underwent liver resection from January 2012 to December 2019 in our institution. We specifically focused on nodules pathologically confirmed benign. Clinicopathological characteristics of these patients were collected. Results From 2012 to 2019, a total of 2632 CRC patients received liver resection for liver nodules, among which 2584 cases were proved to be malignant, and 48 cases were benign. Among these 48 cases, 24 were pathologically confirmed as focal nodular hyperplasia (FNH), 10 were inflammatory lesions, 9 were peliosis, and 5 were hemangioma. At least one pre-operative imaging examination (MRI, US, or PET-CT) indicated CRLM, while no one underwent gadoxetic acid-enhanced MRI. The median size of nodule was 2.0 cm (range, 0.4-8.0 cm). For therapy, ten patients received laparoscopic surgery, and 38 patients received open surgery; ten patients received chemotherapy after discovery of liver nodules. Conclusions Newly detected liver nodules with a history of colorectal cancer could be benign. Gadoxetic acid-enhanced MRI should be considered especially for indeterminate liver nodules that would be mimicker of colorectal cancer liver metastasis.

Pharmacoeconomic Study on the Application of Magnetic Resonance Imaging with Gadoxetic Acid in Addition to Contrast-Enhanced Computed Tomography in Diagnosis of Hepatocellular Carcinoma

Objective: to evaluate pharmacoeconomic advantages of the application of magnetic resonance imaging (MRI) with hepatobiliary-specific contrast agent – gadoxetic acid in addition to contrast-enhanced computed tomography (CT) in the diagnosis of hepatocellular carcinoma (HCC).Material and methods. We performed the modeling and obtained the results of the pharmacoeconomic study: effectiveness analysis, cost analysis, and cost-effectiveness analysis. The cost analysis included only direct medical costs (the cost of contrast-enhanced CT, gadolinium-based contrast agent (GBCA) for MRI, and therapy per a patient with verified HCC diagnosis after diagnostic procedures). The financing was performed from the Compulsary Health Insurance Fund. The calculations were made per 1 patient.Results. The effectiveness analysis showed that the diagnostic scheme CT + MRI with gadoxetic acid was the most effective complex for the diagnosis of HCC because its application provided 50% of patients with 5-year overall survival (4.8 years), which was significantly higher than in patients who were diagnosed HCC with CT + MRI with extracellular GBCA (2.3 years) or CT (3.7 years). The cost-effectiveness analysis showed that the diagnostic scheme with gadoxetic acid was dominant because each disability-adjusted life year required fewer costs (14 862 rubles) in comparison with CT + MRI with extracellular GBCA (25 293 rubles) or CT (46 540 rubles). According to the results of the incremental cost-effectiveness ratio analysis, the application of the diagnostic complex with gadoxetic acid was characterized by the lowest rate of additional costs per 1 disability-adjusted life year.Conclusion. The pharmacoeconomic study showed that the application of MRI with a hepatospecific contrasting agent – gadoxetic acid in addition to contrast-enhanced CT was an effective and economically beneficial method of early HCC diagnosis.